The present invention relates generally to a seat, and more particularly but not exclusively to a vehicle seat such as is used in motor vehicles and the like.
Still more specifically, the invention relates to an adjustment for raising and lowering the seat in a seat structure.
It is known in the prior art to provide an arrangement for adjusting the height of a motor vehicle seat by having a straight-line elongated carrying bracket which is pivotally attached at one of its ends to the seat frame, and at the other end to the seat on the frame, that is the support element for the seat. The angle at which the carrying bracket is inclined with reference to the support element and the seat frame, and the length of the bracket, determine the distance between the seat frame and the support element in the prior art. One end of a supporting lever is pivotally mounted approximately at the mid-point of the bracket, in bearings on the underframe, so as to be movable and capable of being arrested. The angle of inclination of the bracket, and therefore the distance between the seat frame and the under frame, can be regulated by displacement of that end of the supporting lever which is movably mounted in bearings.
It is a disadvantage of the prior-art constructions that they require even in the completely retracted state a relatively large amount of space. This is disadvantageous because the under frame or support element of a motor vehicle seat must, for instance, accept hydraulic or pneumatic elements for damping of vibrations, load adjustment and the like, such as shock absorbers, and must in addition have sufficient floor clearance. In such constructions the prior-art arrangements for seats that can be raised and lowered are frequently not usable, because their installation height is such as to preclude their use due to space limitations. Attempts to overcome these problems have been made, but have invariably succeeded only in lowering the installation height of the seat at the expense of the desired optimum adaptation of the seat to the physical characteristics of a particular occupant.